Generally, in the field of telecommunications, communication transmissions are facilitated by the use of communication platforms (e.g. relay stations). These communication platforms include any vehicle, manned or unmanned, that passes over, or hovers over a territorial coverage region, ranging from typical altitudes of manned and unmanned aircraft (UAVs) and lighter than air (LTA) platforms, to communication satellites in any orbit, not just of the Earth but of any celestial object such as the Moon or Mars.
Orbiting communication satellites facilitate communication between two or more radio terminals on the Earth. Such satellites employ antennas to focus the energy of communication signals towards specific regions of the Earth disc within the satellites' field of view or coverage area. Conventionally, communication satellites operate as simple frequency-converting radio repeaters; they receive signals from Earth station terminals uplinked in one or more bands of the radio frequency spectrum designated for satellite downlinks, and amplify the frequency-converted signals before downlinking the information to other Earth station terminals. Some communication satellites may manipulate or modify the communicated information, such as by demodulating the downlinks in a different format, but most often the signals are simply frequency converted and amplified without such manipulation.
Early communications satellites employed broad beamwidth antennas producing a single beam servicing the entire Earth disc. Some later satellites, with an aim towards providing greater aggregate communication capacity, subdivide the Earth disc into several smaller coverage beam areas, giving each beam greater focused power and enabling the uplink/downlink spectrum to be reused between the beams. However, multiple beam satellites suffer several impediments
One impediment is that typical multiple beam satellites require incremental increases in satellite hardware for each additional beam they produce. This additional hardware not only increases cost of the satellite, but also constrains the number of beams the satellite is capable of sending and receiving due to the state-of-the-art mass and volume limits of the rockets which launch them into orbit. An invention which produced more beams without correspondingly increasing satellite hardware would be useful.
Another impediment is that typical communication satellites create beams whose angular directions are fixed relative to the satellites' attitude reference frame. To keep the beams pointed towards the desired positions upon the Earth disc, the spacecraft is forced to maintain increasingly more precise and accurate attitude control as the angular size of the beams become smaller. This limits the minimum size of communication beams that can be practically employed, as well as limiting the capacity performance of the beams. Thus, an invention which produced beams that could be directed towards points on the Earth independent of the satellite's attitude would be useful.
Yet another impediment of typical multiple beam satellites is that they are often, by construction, inflexible in their ability to relocate communication capacity resources between their multiple beams. For example, often, the configuration of discrete amplifiers and bandpass filters in the satellite limit the service capacity of individual beams below the total available power or bandwidth allocated to the set of beams in whole. A related impediment of typical multiple beam communication satellites is that their beams are usually stationary in relative position to each other or, if adjustable, must be adjusted by some method of side coordination and command. Even when such adjustments are made possible, they add cost and complexity to the satellite, both in construction and in operation. Thus, an invention which simply and automatically reconfigured individual beam bandwidths, powers, and angular directions would be useful.